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How is non-small cell lung cancer diagnosed?

If you have symptoms of lung cancer, you should go to your doctor. After asking questions about your health and doing a physical exam, your doctor might want to do some tests if he or she thinks you might have lung cancer:

Imaging tests

There are a number of different tests that can make pictures of the inside of your body. These can be used to find lung cancer, to see if it has spread, to find out whether treatment is working, or to spot a cancer that has come back after treatment.

Chest x-ray

A plain x-ray of your chest is often the first test your doctor will do to look for any spots on the lungs. If the x-ray is normal, you most likely do not have lung cancer. If anything does not look normal the doctor may order more tests.

CT scan (computed tomography)

A CT (or CAT) scan is a special kind of x-ray test that can show a detailed picture of a slice of your body.

A CT scan is more likely to show a lung tumor than a routine chest x-ray. It can also give the doctor precise information about the size, shape, and place of a tumor, or help find enlarged lymph nodes that might contain cancer. CT scans are used to find tumors in the adrenal glands, liver, brain, and other organs, too.

A CT scan can also be used to guide a biopsy needle (see below) right into a place that might have cancer. To have this done, you stay on the CT scanning table while the doctor moves a biopsy needle through the skin and into the mass. A biopsy sample is then removed and looked at under a microscope.

MRI scan (magnetic resonance imaging)

Like CT scans, MRI scans give detailed pictures of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays. MRI scans are useful in looking for the spread of lung cancer to the brain or spinal cord.

MRI scans take longer than x-rays – often up to an hour. Also, you have to be placed inside a tube-like machine, which upsets some people. Special “open” MRI machines can sometimes help with this if needed.

PET scan (positron emission tomography)

For aPET scan, a form of radioactive sugar is injected into the blood. Cancer cells in the body absorb large amounts of the sugar. A special camera can then spot the radioactivity.

If you appear to have early stage lung cancer, this test can help show if the cancer has spread to nearby lymph nodes or other areas, which can help determine if surgery may be an option for you. This test can also help tell whether an abnormal area on a chest x-ray or CT scan might be cancer.

Special machines combine a CT and a PET scan to even better pinpoint tumors. This is called a PET/CT and is the most common form of PET used for patients with lung cancer.

Bone scan

A bone scan can help show if a cancer has spread to the bones. For this test, a small amount of radioactive substance is put into your vein. The amount used is very low. This substance builds up in areas of bone that may not be normal because of cancer. These will show up on the scan as “hot spots.” While these areas may suggest the spread of cancer, other problems can also cause hot spots.

PET scans, which are often done in people with non-small cell lung cancer, can usually show the spread of cancer to bones, so bone scans aren’t needed very often. Bone scans are done mainly when other test results aren’t clear.

Tests to diagnose lung cancer

The actual diagnosis of non-small cell lung cancer is made by looking at lung cells under a microscope. The cells can be taken from lung secretions (sputum or phlegm), removed from the lung (known as a biopsy), or found in fluid removed from the area around the lung. The choice of which tests to use depends on the situation.

Sputum cytology

In this test, a sample of mucus you cough up from the lungs (called sputum or phlegm) is looked at under a microscope to see if cancer cells are present. This test is more likely to help find cancers that start in the big airways of the lung.

Needle biopsy

For this test, a long, hollow needle is used to remove a sample of cells from the area that may be cancer. If the area is in the outer part of the lungs, the biopsy needle can be inserted through the skin on the chest wall. An imaging test (like a CT scan) is used to guide the needle to the right spot. The sample is looked at in the lab to see if there are cancer cells in it.

A needle biopsy may also be done during a bronchoscopy (see below) to take samples of lymph nodes between the lungs.

Thoracentesis

If fluid has built up around the lungs, this test can be done to check whether it is caused by cancer or by some other medical problem, such as heart failure or an infection. First, the skin is numbed and then a hollow needle is placed between the ribs to drain the fluid. The fluid is checked for cancer cells.

Samples from biopsies or other tests are sent to a lab. There, a doctor looks at the samples under a microscope to find out if they contain cancer and if so, what type of cancer it is. Special tests may be needed to help classify the cancer. Cancers from other organs can spread to the lungs. It’s very important to find out where the cancer started, because treatment is different for different types of cancer.

The results of these tests are described in a pathology report, which is usually available within about a week. If you have any questions about your pathology results or any tests, talk to your doctor. For more information on understanding your pathology report, see the “Lung Pathology” section of our website.

Tests to look for cancer spread in the chest

Bronchoscopy

A lighted, flexible tube (called a bronchoscope) is passed through the mouth or nose and into the larger airways of the lungs. The mouth and throat are sprayed first with a numbing medicine. You may also be given medicine through an intravenous (IV) line to make you feel relaxed. This test can help the doctor see tumors, or it can be used to take samples of tissue or fluids to see if cancer cells are present.

Endobronchial ultrasound

Ultrasound is a test that uses sound waves to make pictures of the inside of your body. For endobronchial ultrasound, a bronchoscope is fitted with an ultrasound device at its tip and is passed down into the windpipe to look at nearby lymph nodes and other structures in the chest. If enlarged lymph nodes are seen on the ultrasound, a hollow needle can be passed through the bronchoscope and guided into the area to take biopsy samples. The samples are then looked at under a microscope to see if cancer cells are present.

Endoscopic esophageal ultrasound

This test is much like an endobronchial ultrasound, except that an endoscope (a lighted, flexible tube) is passed down the throat and into the esophagus (the swallowing tube that connects the mouth to the stomach). This test is done with numbing medicine and drugs to make you sleepy (light sedation).

The esophagus lies just behind the windpipe. Ultrasound images taken from inside the esophagus can help find large lymph nodes inside the chest that might contain lung cancer. If enlarged lymph nodes are seen on the ultrasound, a hollow needle can be passed through the endoscope to get biopsy samples of them. The samples are then looked at under a microscope to see if they contain cancer cells.

Mediastinoscopy and mediastinotomy

Both of these tests let the doctor look at and take samples of the structures in the area between the lungs (called the mediastinum). These tests are done in an operating room while you are in a deep sleep (under general anesthesia). The main difference between them is that a mediastinotomy involves a slightly larger cut (incision), a little lower down on the chest.

Thoracoscopy

This test can be done to find out if cancer has spread to the spaces between the lungs and the chest wall, or to the linings of these spaces. It can also be used to sample tumors on the outer parts of the lungs. It is done in an operating room while you are in a deep sleep (under general anesthesia). The doctor makes a small cut in the skin on the side of the chest and uses a thin, lighted tube connected to a video camera and screen to look at the space between the lungs and the chest wall. Samples of tumor or lymph nodes can be removed and sent to the lab to look for cancer.

Thoracoscopy can also be used as part of the treatment to remove part of a lung in some early-stage lung cancers. This type of operation, known as video-assisted thoracic surgery (VATS), is described in more detail in the “Surgery” section.

Other tests

Blood tests

Blood tests are not used to find lung cancer, but they are done to get a sense of a person’s overall health. A complete blood count (CBC) shows whether your blood has normal numbers of different blood cell types. This test will be done often if you are treated with chemo because these drugs can affect the blood-forming cells of the bone marrow. Other blood tests can spot problems in different organs such as the kidneys, liver, and bones.

Pulmonary function tests

Pulmonary function tests (PFTs) show how well your lungs are working. This is especially important if surgery might be an option in treating the cancer. These tests can give the surgeon an idea if all or part of one of your lungs can be removed or if you are healthy enough for surgery in the first place. For these tests, you breathe in and out through a tube that is connected a machine that measures airflow.